This research project involves the prospective study of the psychology of fertility behavior in women during their childbearing years. There are three groups of women being studied: an unmarried group; a just-married group; and a just-mothered group (First child). In each group there are between twenty-five and thirty-five women at each age level from ages 18 through 27. The study includes 960 experimental subjects. These women have been interviewed for an hour and a half and given a battery of psychological tests, including two general personality inventories, a sexual attitude questionnaire, a contraceptive attitude questionnaire, a maternal attitude questionnaire; a feminine interest questionnaire; and a sexual and contraceptive knowledge test. Spouses of the just-married and just-mothered groups have also been given one of the personality inventories, and a spouse attitude questionnaire which briefly covers most of the behavioral domains explored in more detail with the woman. The study sample has been selected randomly from the San Francisco Bay Area. A control group of 114 women (38 from each of the three groups) is also included. This group has not undergone antecedent interview and testing but will be followed up in the same manner as the experimental group. The follow-up period covers five years. Once each year for that duration, each woman will be contacted by telephone and interviewed regarding significant intervening fertility events. At the end of the five-year period, the women will be re-interviewed in depth and retested. This study will provide longitudinal information about the effects of psychological characteristics at different points in the life cycle upon subsequent fertility events such as the frequency and spacing of conception and childbirth. It will also allow a prospective psychological study of other behaviors such as marriage, sexuality, contraception, divorce, abortion, and sterilization, all of which have a direct bearing upon subsequent fertility. While the study is primarily concerned with the psychological factors which influence fertility behavior in women, the large amount of additional data gathered from their spouses will greatly enrich our understanding of couple interaction and fertility behavior.